Synchronizing method and apparatus

Abstract

A method and apparatus is disclosed for performing a synchronization of an incoming series of complex samples of an incoming signal with a known sequence of a plurality of coefficients which represents a pattern within the incoming signal, known to the synchronizer, where the synchronization is performed using a plurality of cross-correlations units.

1. A method of synchronizing an incoming signal, said method comprising:
 extracting a real part and an imaginary part of the incoming signal and a real part and an imaginary part of a sequence of at least one known coefficient; 
 extracting a sign for each of the extracted real part and imaginary part of the incoming signal, and the extracted real part and imaginary part of the sequence of at least one coefficient; 
 correlating said extracted sign of the extracted real part and imaginary part of the incoming signal and said extracted sign of the real part and imaginary part of the sequence of at least one coefficient to obtain a correlated signal; 
 selecting said correlated signal when said correlated signal matches a given criterion; and 
 synchronizing said incoming signal with said at least one known coefficient using said selected correlated signal wherein said extracting a sign comprises applying a signum function defined as sgn (f)=1 when f≧0 and sgn (f)=−1 when f<0. 
 
   
   
     2. The method as claimed in  claim 1 , further comprising mapping the extracted sign of the real and imaginary part of the incoming signal and the real and imaginary part of the at least one known coefficient equal to one of 0 and 1, and further wherein said correlating comprises correlating said mapped extracted sign of the real and imaginary part of the incoming signal with said at least one known coefficient to obtain said correlated signal. 
   
   
     3. The method as claimed in  claim 1 , wherein said correlating comprises using a XOR function. 
   
   
     4. The method as claimed in  claim 1 , wherein wherein said correlating is performed using at least said sequence of known coefficients to provide a plurality of correlated signals, further wherein said selecting comprises generating a value indicative of a synchronization between said sequence of known coefficients and said transmitted signal and selecting said correlated signals from said plurality of correlated signals when said synchronization indicative value matches said given criterion. 
   
   
     5. The method as claimed in  claim 4 , wherein said criterion is selected from a group consisting of the maximum value of said synchronization indicative value, a statistical function depending on said synchronization indicative value and a threshold value for said synchronization indicative value. 
   
   
     6. The method as claimed in  claim 1 , further comprising the step of providing said given criterion. 
   
   
     7. The method as claimed in  claim 1 , wherein said criterion is selected from a group consisting of the maximum value of said correlated signal, a statistical function depending on said correlated signal and a threshold value for said correlated signal. 
   
   
     8. A synchronizer for synchronizing a known sequence of coefficients, said sequence of coefficients having a real part and an imaginary part, to an incoming input signal, said incoming input signal having a real part and an imaginary part, the synchronizer comprising:
 a calculator for extracting a sign for each of the real part and imaginary part of the sequence of coefficients, and real part and imaginary part of the incoming input signal; 
 a first correlation unit for correlating said sign of said imaginary part of said incoming input signal with said sign of said imaginary part of said sequence of at least one coefficient to provide a first correlated signal; 
 a second correlation unit for correlating said sign of said real part of said incoming input signal with said sign of said real part of said sequence of at least one coefficient to provide a second correlated signal; 
 a third correlation unit for correlating said sign of said imaginary part of said incoming input signal with said sign of said real part of said sequence of at least one coefficient to provide a third correlated signal; 
 a fourth correlation unit for correlating said sign of said real part of said incoming input signal with said sign of said imaginary part of said sequence of at least one coefficient to provide a fourth correlated signal; 
 a first adding unit subtracting said first correlated signal and said second correlated signal to “4” to provide a first added signal; 
 a second adding unit subtracting said third correlated signal and adding said fourth correlated signal to provide a second added signal; and 
 a criterion matching unit determining which of said first added signal and said second added signal matches a given criterion. 
 
   
   
     9. A synchronizer for determining when an incoming signal, having an arbitrary power value, matches at least one known coefficient, said synchronizer comprising:
 a quantizer determining a quantization bit indicative of said arbitrary power value, the quantizer applying a signum function to said arbitrary power value to obtain the quantization bit; 
 a correlator to correlate said quantization bit with said at least one known coefficient to obtain a correlated signal; and 
 a selector to select said correlated signal when said correlated signal matches a given criterion. 
 
   
   
     10. The synchronizer as claimed in  claim 9 , wherein said quantizer comprises a calculator for applying a signum function to said arbitrary power value, said signum function being defined as sgn (f)=1 when f≧0 and sgn (f)=−1 when f<0. 
   
   
     11. The synchronizer as claimed in  claim 10 , wherein said quantizer further comprises a mapping unit to provide a mapped quantization bit equal to one of 0 and 1 after applying said signum function, further wherein said at least one known coefficient is equal either to one of 0 and 1 and further wherein said correlator correlates said mapped quantization bit with said at least one known coefficient to obtain said correlated signal. 
   
   
     12. The synchronizer as claimed in  claim 9 , wherein said at least one known coefficient comprises a sequence of known coefficients, further wherein said correlator correlates said sequence of known coefficients to provide a plurality of correlated signals, further wherein said selector generates a value indicative of a synchronization between said sequence of known coefficients and said incoming signal and further selects the correlated signals from said plurality of correlated signals when said synchronization indicative value matches said given criterion. 
   
   
     13. The synchronizer as claimed in  claim 9 , wherein at least one of said quantizer, said correlator and said selector is implemented in one of a Field Programmable Gate Array (FPGA) and an Application Specific Integrated Circuit (ASIC).